Only Nvidia does CUDA.
ATI does CAL or OpenCL at Seti but only if you use a third party application, such as the one from Lunatics. Seti does not have a default ATI application of its own yet.

Doing CUDA work on an ATI card is not possible. Work appointed for your CUDA card (Nvidia Fermi) will either have to time out, or you have to abort all of them and report them. Or put the Fermi card back in, of course.Jord

Ancient Astronaut Theorists suggest that in many ways, you can be considered an alien conspiracy!